Thermal Storage Device with Immiscible Storage Media

Abstract

A thermal storage system includes a container, a thermal exchange device, a first thermal storage material, and a second thermal storage material. The first thermal exchange device is disposed in the container. The first thermal storage material is disposed in the container and is spaced apart from the thermal exchange device. The second thermal storage material is also disposed in the container in contact with the thermal exchange device. The first and second thermal storage materials are immiscible. The second thermal storage material is less reactive with the construction material of the thermal exchange device as compared to the first thermal storage material. Optionally, a second thermal exchange device can be submerged in the second thermal storage material. The first thermal exchange device is configured to supply heat to the second thermal storage material and the second thermal exchange device facilitates extraction of heat from the second thermal storage material.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of priority of co-pending U.S. Provisional Patent Application No. 63 / 083,797, filed Sep. 25, 2020 by the same inventors, which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTIONField of the Invention[0002]This invention relates generally to heat transfer, and more particularly to thermal storage systems.Description of the Background Art[0003]Devices designed to store thermal energy fall into two broad categories based on whether they use sensible heat or latent heat as the storage mechanism. Latent heat-based technologies have the merit of delivering energy at a fixed temperature and can have a higher energy density (in J / kg or J / m3) than sensible heat-based technologies. Thermal energy storage systems can also be operated in a combined latent heat and sensible heat mode if the application allows. Such a configuration can potentially double the amount of thermal energy that can be stored for a...

AI Technical Summary

Benefits of technology

The present invention aims to address the issue of thermal storage material reactivity while still allowing for efficient energy extraction and storage. This is achieved by using a new process that involves cooling the phase change material using a cool heat transfer fluid, which results in the solidification of aluminum and tin. The high thermal conductivity of the two metals allows for high power and energy densities, making the device suitable for various applications. The invention also reduces corrosion and avoids potential damage to the container and heat exchangers, allowing for the use of high latent heat of fusion materials.

Problems solved by technology

However, these attempts become confounded by the tendency of the salt to attach to the heat exchanger surface as the material solidifies.

Solid salts typically have a very low thermal conductivity, so as the heat exchange surface becomes coated with solid salt, it impedes the transfer of heat energy and reduces the rate at which energy can be extracted (i.e., it limits the extractable power).

Recent attempts to encapsulate the salt in small spherical capsules that are then held in suspension in a high thermal conductivity fluid have been made to work, but are complex and necessarily reduce the net storable energy density because of the additional materials that only serve to help conduct the heat.

Such approaches tend toward complexity and have not been commercially exploited.

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